1. Field of the Invention
The present invention relates to a method of and device for removing and solidifying hydrocarbon oils and solvents from liquid. More specifically, the present invention relates to a filtration media used to selectively remove oil, solvent and other hydrocarbon compounds from liquid such that the liquid is discharged in a clean state. This method will result in the passive, inexpensive and foolproof filtration of stormwater and process liquid from spill containment areas, process areas, parking lots, and any other potential source of hydrocarbon containing liquid. In the event of a hydrocarbon spill or leak wherein an excess of hydrocarbons contacts the filtration media, the filtration media will form a plug to effectively contain the spill or leak.
2. Description of Related Art
In many commercial and industrial applications and installations, to prevent contamination of the environment by oils and solvents, spill containment systems are built that not only trap the potential spilled liquids but also any process liquid or rain/snow-melt liquid that comes in contact with the spill containment area. Federal, state and local regulations that mandate spill protection to minimize or eliminate hydrocarbon discharges to the environment are becoming more and more strict. The challenge is not just to prevent the spill, but to be able to handle the rainwater or process liquid that could be contaminated with hydrocarbons. With stormwater quality regulations being applied to parking lots and roofing systems, the difficulty is not just handling the hydrocarbons, but separating it efficiently and economically from a large quantity of stormwater.
Measures to separate oil and solvents from liquid are well known in the art. Passive means of separating oil and solvents from liquid typically use weirs of various heights to allow the oil and solvents which are lighter than liquid to be concentrated by collection or containment above the weirs. The liquid layer flows under the weirs in a somewhat cleaned state. These separators are far from 100% effective and are utilized only under very specific conditions. However, those conditions are not practicable with stormwater or spill containment area liquid discharges.
A popular mechanical means known in the art is moving a fabric belt through the liquid and oil mixture. As the fabric belt moves through the liquid and oil mixture, the fabric absorbs some of the oil. The belt is then squeezed through a device which removes the oil thereby separating the oil from the liquid. Such a device is rather crude, requires constant maintenance and power to operate, and it simply cannot remove all of the oil/solvent. Discharge of the liquid, even after cleaning by such a separator, would result in a significant amount of hydrocarbons being delivered into the environment.
Another mechanical device uses centrifugal force to separate the liquid from the lighter oils and solvents. As with the belt-type device described earlier, the centrifuge method requires a great deal of maintenance, a significant investment in equipment and it is simply not practical for the application of stormwater/spill containment area liquid discharge.
Chemical means known in the art for separating hydrocarbons from liquid employ specific absorbents or adsorbents. Adsorbents such as vermiculite, sand, oleophilic clays, tree bark and other similar materials merely hold the oil and solvents on their surface. However, in a passive filtration system, the liquid flow would pull a substantial amount of the oil and solvent off the surface of the solid adsorbent. Not only are these materials substantially ineffective, but in the event of a major hydrocarbon spill or leak, these materials allow the hydrocarbons to pass through to the environment.
Polymeric absorbents, mainly in booms and pillows, are also used to selectively absorb hydrocarbons from standing liquid and liquid systems. Typically, the granular absorbent materials solidify upon absorption of hydrocarbons. However, absorbents of this type are undesirable in a passive filtration system since the solidification of the absorbents would only absorb the bulk floating hydrocarbons while allowing sheen to be discharged.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a passive device for separating hydrocarbons from stormwater or spill containment areas capable of plugging and sealing off the containment area in the event of hydrocarbon overload as in a spill or leak.
It is another object of the present invention to provide a passive method for separating hydrocarbons from stormwater or spill containment areas capable of plugging and sealing off the containment area in the event of hydrocarbon overload as in a spill or leak.
It is yet another object of the present invention to provide a method of and device for filtering out hydrocarbons utilizing existing drainage and filtration resources capable of plugging and sealing off the containment area in the event of hydrocarbon overload as in a spill or leak.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.